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54841ab50c
The hush shell dynamically allocates (and re-allocates) memory for the
argument strings in the "char *argv[]" argument vector passed to
commands. Any code that modifies these pointers will cause serious
corruption of the malloc data structures and crash U-Boot, so make
sure the compiler can check that no such modifications are being done
by changing the code into "char * const argv[]".
This modification is the result of debugging a strange crash caused
after adding a new command, which used the following argument
processing code which has been working perfectly fine in all Unix
systems since version 6 - but not so in U-Boot:
int main (int argc, char **argv)
{
while (--argc > 0 && **++argv == '-') {
/* ====> */ while (*++*argv) {
switch (**argv) {
case 'd':
debug++;
break;
...
default:
usage ();
}
}
}
...
}
The line marked "====>" will corrupt the malloc data structures and
usually cause U-Boot to crash when the next command gets executed by
the shell. With the modification, the compiler will prevent this with
an
error: increment of read-only location '*argv'
N.B.: The code above can be trivially rewritten like this:
while (--argc > 0 && **++argv == '-') {
char *arg = *argv;
while (*++arg) {
switch (*arg) {
...
Signed-off-by: Wolfgang Denk <wd@denx.de>
Acked-by: Mike Frysinger <vapier@gentoo.org>
105 lines
2.5 KiB
C
105 lines
2.5 KiB
C
/*
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* (C) Copyright 2005 - 2006
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* Martin Krause, TQ-Systems GmbH, martin.krause@tqs.de.
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*
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* See file CREDITS for list of people who contributed to this
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* project.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation; either version 2 of
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* the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston,
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* MA 02111-1307 USA
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*/
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/*
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* TB5200 specific functions
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*/
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/*#define DEBUG*/
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#include <common.h>
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#include <command.h>
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#if defined(CONFIG_CMD_BSP)
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#if defined (CONFIG_TB5200)
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#define SM501_PANEL_DISPLAY_CONTROL 0x00080000UL
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static void led_init(void)
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{
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struct mpc5xxx_gpt_0_7 *gpt = (struct mpc5xxx_gpt_0_7 *)MPC5XXX_GPT;
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/* configure timer 4 for simple GPIO output */
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gpt->gpt4.emsr |= 0x00000024;
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}
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int cmd_led(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
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{
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struct mpc5xxx_gpt_0_7 *gpt = (struct mpc5xxx_gpt_0_7 *)MPC5XXX_GPT;
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led_init();
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if (strcmp (argv[1], "on") == 0) {
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debug ("switch status LED on\n");
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gpt->gpt4.emsr |= (1 << 4);
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} else if (strcmp (argv[1], "off") == 0) {
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debug ("switch status LED off\n");
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gpt->gpt4.emsr &= ~(1 << 4);
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} else {
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printf ("Usage:\nled on/off\n");
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return 1;
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}
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return 0;
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}
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static void sm501_backlight (unsigned int state)
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{
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if (state == 1) {
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*(vu_long *)(SM501_MMIO_BASE+SM501_PANEL_DISPLAY_CONTROL) |=
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(1 << 26) | (1 << 27);
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} else if (state == 0)
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*(vu_long *)(SM501_MMIO_BASE+SM501_PANEL_DISPLAY_CONTROL) &=
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~((1 << 26) | (1 << 27));
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}
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int cmd_backlight(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
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{
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if (strcmp (argv[1], "on") == 0) {
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debug ("switch backlight on\n");
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sm501_backlight (1);
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} else if (strcmp (argv[1], "off") == 0) {
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debug ("switch backlight off\n");
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sm501_backlight (0);
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} else {
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printf ("Usage:\nbacklight on/off\n");
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return 1;
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}
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return 0;
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}
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U_BOOT_CMD(
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led , 2, 1, cmd_led,
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"switch status LED on or off",
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"on/off"
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);
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U_BOOT_CMD(
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backlight , 2, 1, cmd_backlight,
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"switch backlight on or off",
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"on/off"
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);
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#endif /* CONFIG_STK52XX */
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#endif
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